1. Field of the Invention
This invention relates to a lever-type connector used mainly for connecting wire harnesses together in an automobile, which connector can be operated with a low insertion/withdrawal force.
2. Background
One conventional, well-known connector of the type described is disclosed in Japanese Patent Unexamined Patent Publication No. 4-87169, which connector employs a spring as shown in FIGS. 8 and 9.
In FIG. 8, a female connector 102 includes a pivotal cam lever 103 having a lock projection 104, and the cam lever 103 is urged upwardly by a coil spring 106 mounted on a support shaft provided at an inner end thereof. A male connector 101, having a lock portion 108, is inserted at its front end portion into a front opening in the female connector 102, and then when the cam lever 103 is lowered from its raised position, the male connector is further inserted into a predetermined position within the female connector 102 with a low fitting force thanks to leverage achieved by the cam lever 103, thereby making an electrical connection between the two connectors.
As the cam lever 103 is thus lowered from its raised position after the male connector 101 is inserted into the front opening in the female connector 102, the lock projection 104 of the cam lever 103 presses down the lock portion 108 of a lock arm 107 of the male connector 101, with a slanting engagement portion 105 of the lock projection 104 held in sliding contact with a slanting engagement portion 109 of the lock portion 108, and when the two connectors are completely fitted together, the lock projection 104 slides past the lock portion 108 to be held against a lower surface of the lock portion 108, so that the two connectors are held in a completely-fitted or retained condition as shown in FIG. 9.
Here, if the cam lever 103 is held in its lowered position during the fitting of the male connector 101 into the female connector 102, the male connector 101 is prevented from advancing, and can not be inserted any further. The coil spring (resilient member) 106 is provided for overcoming this, and with this construction the cam lever 103 is urged into its initial or raised position by the resilient force of the coil spring 106 so that the cam lever will not prevent the male connector from advancing.
When the two connectors 101 and 102 have not yet been completely fitted together, the lock projection 104 is not retainingly engaged with the lock portion 108, so that the cam lever 103 is kept raised as shown in FIG. 8. This enables the incomplete fitting between the two connectors 101 and 102 to be easily found or confirmed.
In the above conventional technique, however, there must be provided the resilient member (the coil spring in the above example), such as a spring, which holds the cam lever (retaining lever) 103 in its predetermined initial position during the connector fitting operation, and also facilitates the confirmation of the incomplete fitting. Therefore, it has been difficult to provide the low-cost connector.
And besides, the resilient member always acts in such a manner as to urge the retaining lever back even in the completely-fitted condition, so that stresses are always applied to the engagement portions. This has resulted in a problem that even when a small external force is applied, the two connectors could be easily disengaged from each other. In addition, since stresses are always applied to the engagement portions, there has been encountered a problem that the engagement portions have been liable to damage or to deterioration due to aging.
Another problem of the conventional technique is that if an unexpectedly-large external force (impact) is accidentally applied to the retaining lever in the completely-fitted condition, the engagement portions were destroyed in an unrecoverable manner or damaged since there has not been provided any means for relieving such accidental impact force.